Transverse field type liquid crystal display panel

ABSTRACT

A transverse field type liquid crystal display panel has multiple scan lines  12  and common wires  13  provided in parallel, multiple signal lines  17  provided in the direction crossing the scan lines  12 , and common electrodes  14  and pixel electrodes  21  formed in the regions delimited by the multiple scan lines  12  and signal lines  17 . At least part of the surface of an insulator laid over the scan lines  17  is covered by shield electrodes  22  constituted of a conductive material. Thanks to such structure, there can be provided a transverse field type—that is, an IPS mode or FFS mode—liquid crystal display panel that is equipped with a device for preventing burn-in due to the voltage that is applied to the scan lines.

BACKGROUND

1. Technical Field

The present invention relates to an in-plane switching (IPS) mode orfringe field switching (FFS) mode transverse field type liquid displaypanel, and more particularly to an IPS or FFS mode liquid crystaldisplay panel that is equipped with a device for preventing burn-inarising from the voltage that is applied to the scan lines.

2. Related Art

Recent years have seen widespread use of liquid crystal display panelsnot only in telecommunications equipment but in electrical equipment ingeneral. The liquid crystal display panels that have long been in useare made up of a pair of substrates of glass or the like with electrodesand so on formed on their surfaces, and a liquid crystal layer formedbetween such pair of substrates. Images of various types are displayedby the application of voltage to the electrodes on the two substrates,which rearranges the liquid crystals, altering the transmittance oflight therethrough. This is what may be called the “longitudinal fieldtype”. Among such longitudinal field type liquid crystal display panelsthere exist those with a twisted nematic (TM) mode or vertical alignment(VA) mode, which however have the problem that their viewing angle isnarrow. Accordingly, longitudinal field type liquid crystal displaypanels with various improvements such as multidomain vertical alignment(MVA) mode have been developed.

On the other hand, among IPS mode liquid crystal display panels thereare also known those that may be called “transverse field type” and thatdiffer from the longitudinal field type described above in havingelectrodes on one substrate only (see JP-A-10-319371 andJP-A-2002-131767). The operating principles of such an IPS mode liquidcrystal display panel will now be described using FIGS. 10 to 12. FIG.10 is a schematic plan view of a single pixel portion of an IPS modeliquid crystal display panel, FIG. 11 is a cross-sectional view alongline X-X in FIG. 10, and FIG. 12 is a cross-sectional view along lineXI-XI in FIG. 10.

This IPS mode liquid crystal display panel 50A has an array substrate ARand a color filter substrate CF. The array substrate AR has multiplescan lines 52 and common wires 53 provided parallel with one another ona surface of a first transparent substrate 51, and multiple signal lines54 provided in the direction crossing over these scan lines 52 andcommon wires 53. In the central portion of each pixel there is provideda common electrode 55 having for example a comb-like shape as in FIG. 10and extending strip-like from the common wire 53. A pixel electrode 56,likewise of a comb-like shape, is provided so as to enclose the spacesaround the peripheries of the common electrode 55, and the surface ofthe pixel electrode 56 is covered with, for instance, a protectiveinsulator 57 of silicon nitride and an alignment layer 58 of polyimideor the like.

Close to the intersections of the scan lines 52 and signal lines 54there are formed thin film transistors (TFTs) that serve as switchingelements. For each TFT, a semiconductor layer 59 is laid between a scanline 52 and signal line 54; a signal line portion on the semiconductorlayer 59 constitutes the TFT's source electrode S and a scan lineportion below the semiconductor layer 59 constitutes the gate electrodeG, while the drain electrode D is constituted by a part of the pixelelectrode 56 that overlaps part of the semiconductor layer 59.

The color filter substrate CF has a configuration such that a colorfilter layer 61, overcoat layer 62 and alignment layer 63 are providedon a surface of a second transparent substrate 60. To form the IPS modeliquid crystal display panel 50A, the array substrate AR and colorfilter substrate CF are positioned opposing each other so that the pixelelectrode 56 and common electrode 55 on the array substrate AR and thecolor filter layer 61 on the color filter substrate CF face each other,liquid crystal LC is sealed therebetween, and polarizing plates 64 and65 are deposed on the outer side of substrates AR and CF respectively,placed so that their polarization directions cross over each other.

In this IPS mode liquid crystal display panel 50A, when an electricfield is formed between the pixel electrode 56 and common electrode 55,the liquid crystals, which are aligned horizontally, will gyratehorizontally as shown in FIGS. 11 and 12. By means of this it ispossible to control the amount of incident light from the backlight thatis transmitted. This IPS mode liquid crystal display panel 50A has theadvantages of a wide viewing angle and high contrast, but also has theproblems of low aperture ratio and transmittance because the commonelectrodes 55 are formed from the same metallic material as the commonwires 53 or scan lines 52, as well as the problem of color variationdepending on the viewing angle.

FFS mode liquid crystal display panels (see JP-A-2002-14363 andJP-A-2002-244158) have been developed in order to resolve the problemsof low aperture ratio and transmittance in IPS mode liquid crystaldisplay panels. The operating principles of such an FFS mode liquidcrystal display panel will now be described using FIGS. 13 to 15. FIG.13 is a schematic plan view of a single pixel portion of an FFS modeliquid crystal display panel, FIG. 14 is a cross-sectional view alongline XIV-XIV in FIG. 13, and FIG. 15 is a cross-sectional view alongline XV-XV in FIG. 13.

This FFS mode liquid crystal display panel 70A has an array substrate ARand a color filter substrate CF. The array substrate AR has multiplescan lines 72 and common wires 73 provided parallel with one another ona surface of a first transparent substrate 71, and multiple signal lines74 provided in the direction crossing over these scan lines 72 andcommon wires 73. A common electrode (also termed “opposed electrodes”)75 connected to the common wires 73 and formed from indium tin oxide(ITO) or a like transparent material is provided so as to cover eachspace delimited by the scan lines 72 and signal lines 74, and over asurface of the common electrode 75 there are provided, with a gateinsulator 76 interposed, a pixel electrode 78A constituted of ITO or alike transparent material, in which there are formed multiplestripe-like slits 77A. The surfaces of the pixel electrode 78A and themultiple slits 77A therein are covered by an alignment layer 80.

Close to the positions where the scan lines 72 and signal lines 74intersect there are formed TFTs that serve as switching elements. Foreach TFT, a semiconductor layer 79 is laid on a surface of a scan line72, and a portion is extended from a signal line 74 so as to cover partof the semiconductor layer 79's surface and constitute the TFT's sourceelectrode S; a scan line portion below the semiconductor layer 79constitutes the gate electrode G, while a part of the pixel electrode78A that overlaps part of the semiconductor layer 79 constitutes thedrain electrode D.

The color filter substrate CF has a configuration such that a colorfilter layer 83, overcoat layer 84, and alignment layer 85 are providedon a surface of a second transparent substrate 82. To form the FFS modeliquid crystal display panel 70A, the array substrate AR and colorfilter substrate CF are positioned opposing each other so that the pixelelectrode 78A and common electrode 75 on the array substrate AR and thecolor filter layer 83 on the color filter substrate CF face each other,liquid crystal LC is sealed therebetween, and polarizing plates 86 and87 are deposed on the outer side of substrates AR and CF respectively,placed so that their polarization directions are orthogonal to eachother.

In this FFS mode liquid crystal display panel 70A, when an electricfield is formed between the pixel electrode 78A and common electrode 75,the field is oriented toward the common electrode 75 at both sides ofthe pixel electrode 78A, as shown in FIGS. 14 and 15, and consequently,not only does the liquid crystal present at the slits 77A move, but sodoes the liquid crystal present over the pixel electrode 78A. As aresult, The FFS mode liquid crystal display panel 70A has the featuresof having an even wider viewing angle and higher contrast than the IPSmode liquid crystal display panel 50A, and moreover an ability toprovide bright displays thanks to possessing high transmittance. Inaddition, the FFS mode liquid crystal display panel 70A has a greateroverlap area, viewed from above, between the pixel electrode 78A andcommon electrode 75 than has the IPS mode liquid crystal display panel50A, and, as a collateral effect thereof, a larger holding capacity andhence the advantage that no auxiliary capacity line needs to bespecially provided.

In an FFS mode liquid crystal display panel, similarly to the case of anIPS mode liquid crystal display panel, it is preferable for the sake ofthe display characteristics that the rubbing direction should beorthogonal to the signal lines, and the pixel electrodes be provided ata slight inclined angle relative to the rubbing direction. Accordingly,a structure may be adopted whereby stripe-like slits 77B provided in apixel electrode 78B are inclined relative to the scan lines 72 or commonwires 73 as in the FFS mode liquid crystal display panel 70B shown inFIG. 16. Similarly, in order to eliminate color variation depending onthe viewing angle, the stripe-like slits 77C provided in a pixelelectrode 78C may be arranged in two mutually inclined sets, one abovethe other, thus producing dual domains, as in the FFS mode liquidcrystal display panel 70C shown in FIG. 17. Further, the signal lines 72may be provided in a crank-shape in a direction orthogonal to the scanlines 74, and the multiple common electrodes and pixel electrodes 78D bearranged in a delta layout, so that the black matrices provided on thecolor filter substrate at the portions opposed to the signal lines 72will not form straight lines, and the device will be capable of imagedisplays in which the black matrices are inconspicuous, as in the FFSmode liquid crystal display panel 70D shown in FIG. 18.

The FFS mode liquid crystal display panels 70B and 70C shown in FIGS. 16and 17 differ from the FFS mode liquid crystal display panel 70A shownin FIG. 13 only in that the slits 77B and 77C provided in their pixelelectrodes 78B and 78C are inclined. Moreover, the FFS mode liquidcrystal display panel 70D shown in FIG. 18 differs from the FFS modeliquid crystal display panel 70A shown in FIG. 13 only in that slits 77Dprovided in its pixel electrodes 78D are inclined and that its multiplecommon electrodes and pixel electrodes 78D are arranged in a deltalayout. Below therefore, component elements that have identicalstructure to those in the FFS mode liquid crystal display panel 70Ashown in FIG. 13 are assigned the identical reference numerals anddetailed descriptions thereof are omitted.

Also in the IPS mode liquid crystal display panel 50A shown in FIG. 10,it is possible, similarly with the FFS mode liquid crystal displaypanels 70B and 70C described above, and as in the IPS mode liquidcrystal display panel 50B shown in FIG. 19, to improve the displayquality by making the alignment layer's rubbing direction cross thesignal lines 54 and providing a pixel electrode 55B and a commonelectrode 56B at a slight inclined angle relative to the rubbingdirection; and further possible, as in the IPS mode liquid crystaldisplay panel 50C shown in FIG. 20, to eliminate color variationdepending on the viewing angle, by arranging a pixel electrode 55C and acommon electrode 56C each to be inclined in a different extensiondirection, leftward or rightward, thus producing dual domains. Inaddition, although an illustration thereof is omitted among thedrawings, it is also possible with such IPS mode liquid crystal displaypanels 50A, 50B, 50C to arrange the multiple pixel electrodes 55, 55A,55B and common electrodes 56, 56A, 56B in a delta layout so as to obtainan image display in which the black matrices are inconspicuous, as inthe FFS mode liquid crystal display panel 70D shown in FIG. 18.Moreover, the IPS mode liquid crystal display panels 50B and 50C shownin FIGS. 19 and 20 differ from the IPS mode liquid crystal display panel50A shown in FIG. 10 only in that their pixel electrodes 55B, 55C andcommon electrodes 56B, 56C are inclined. Below therefore, componentelements that have identical structure to those in the IPS mode liquidcrystal display panel 50A shown in FIG. 10 are assigned the identicalreference numerals and detailed descriptions thereof are omitted.

Thus, FFS mode liquid crystal display panels have the features of havingan even wider viewing angle and higher contrast than IPS mode liquidcrystal display panels, and moreover of being able to provide brightdisplays thanks to possessing high transmittance. Furthermore they canbe driven with low voltage, and what is more, have a larger holdingcapacity generated as collateral effect, which means that they yieldgood display quality without special provision of auxiliary capacitylines.

However, it is well known that when used for prolonged periods, liquidcrystal display panels are prone to the phenomenon of burn-in. This isthe case both with IPS mode liquid crystal display panels and with FFSmode liquid crystal display panels. But it has been found that theburn-in phenomenon occurs more markedly in related art FFS mode liquidcrystal display panels such as described above than in related art IPSmode liquid crystal display panels. The present inventors inferred, as aresult of many and varied investigations into the causes of the burn-inphenomenon occurring more markedly in the FFS mode liquid crystaldisplay panels than in the IPS mode liquid crystal display panels,that—it being the case that the electrical field produced by the largesignal voltages applied to the scan lines affects the alignment of thenearby liquid crystals—a contributory factor is that whereas in the IPSmode liquid crystal display panels the path of the electrical forcelines oriented from the pixel electrode toward the liquid crystals andthe path of the electrical force lines oriented from the liquid crystalstoward the scan lines are symmetrical, in the FFS mode liquid crystaldisplay panels they are asymmetrical.

More precisely, in IPS and FFS mode liquid crystal display panels, thevoltage applied to the scan lines is approximately −10V in the statewhen given pixels are deselected, and approximately +15V in the statewhen selected, but since the duration for which given pixels areselected is extremely short, DC voltage of approximately −10V is appliedover extended periods. In the case of an IPS mode liquid crystal displaypanel however, as is plain from FIG. 12, an electrical force line E1oriented from the pixel electrode 56 to the scan line 52 enters theliquid crystal layer LC via the pixel electrode 56, protective insulator57, and alignment layer 58, and from the liquid crystal layer LC reachesthe scan line 52 via the alignment layer 58 and protective insulator 57;thus, the force line's path in traveling from the pixel electrode 56 tothe liquid crystal layer LC is symmetrical with the path thereof intraveling from the liquid crystal layer LC to the scan line 52.

In an FFS mode liquid crystal display panel by contrast, as is plainfrom FIG. 15, an electrical force line E2 oriented from the pixelelectrode 78A to the scan line 72 enters the liquid crystal layer LC viathe pixel electrode 78A and alignment layer 80, but from the liquidcrystal layer LC reaches the scan line 72 via the alignment layer 80 andgate insulator 76. Thus, the force line's path in traveling from thepixel electrode 78A to the liquid crystal layer LC is asymmetrical withthe path thereof in traveling from the liquid crystal layer LC to thescan line 72. As a result, in the FFS mode liquid crystal display panelthe pixel electrode and/or the alignment layer on the surface thereofare more prone than in the IPS mode liquid crystal display panel to beirreversibly affected by the DC field arising from the signals appliedto the scan lines 72. This is inferred to be the reason why the burn-inphenomenon occurs more markedly in the FFS mode liquid crystal displaypanel than in the IPS mode liquid crystal display panel.

SUMMARY

The inventors arrived at the present invention when they discovered, asa result of intensive and extensive investigations to alleviate theproblem of burn-in with such FFS mode liquid crystal display panels,that although in FFS mode liquid crystal display panels it isproblematic, due to the operating principles thereof, to rendersymmetrical the path of the electric field lines from the pixelelectrodes to the liquid crystal layer and the path thereof from theliquid crystal layer to the scan lines; nevertheless, by ensuring thatthe DC field arising from the high voltage signals applied to the scanlines is not applied to the nearby liquid crystals, it is possible toreduce burn-in not only in FFS mode liquid crystal display panels but inIPS mode liquid crystal display panels also.

JP-A-2002-131767 discloses an IPS mode liquid crystal display panel inwhich partially superposed conductive layers are provided over thesignal lines or the scan lines or both, with the purpose of preventingthe light leak that will occur if the liquid crystals are driven by theelectric field that arises between the signal lines (drain signal lines)or scan lines (gate signal lines) and the electrodes deposed adjacentthereto. However, although suggestions partially concerning FFS modeliquid crystal display panels are contained therein (see paragraphs[0003] and [0004]), no specific instance of an FFS mode liquid crystaldisplay panel is described therein. Nor is there any hint thereinconcerning burn-in problems in either IPS mode or FFS mode liquidcrystal display panels.

An advantage of some aspects of the present invention is to provide atransverse field type—that is, an IPS mode or FFS mode—liquid crystaldisplay panel that has a device for preventing burn-in due to thevoltage applied to the scan lines.

According to an aspect of the invention, a transverse field type liquidcrystal display panel includes multiple scan lines and common wiresprovided in parallel, multiple signal lines provided in a directioncrossing the scan lines, and common electrodes and pixel electrodesformed in regions delimited by the scan lines and signal lines, and hasthe feature that shield electrodes constituted of a conductive materialare formed on a surface of an insulator lying over the scan lines.

In another aspect of the invention, the shield electrodes may beelectrically connected to the common electrodes.

In another aspect, the shield electrodes may partially have cut-awaysprovided close to the shield electrodes, and the shield electrodes beextended to above the insulator at the cut-aways and electricallyconnected to the common electrodes via contact holes provided in thecut-aways.

In another aspect, the shield electrodes may be electrically connectedto the signal lines.

In another aspect, the shield electrodes may be extended over thesurface of the insulator over the scan lines as far as the intersectionsof the scan lines and signal lines, and be electrically connected to thesignal lines via contact holes provided at the intersections.

In another aspect, the pixel electrodes may partially have cut-awaysprovided adjacent to the two sides of the scan lines, and the shieldelectrodes may be extended to above the surface of the insulator overthe cut-aways and be electrically connected to each of the commonelectrodes located on the two sides of the scan lines via contact holesprovided in the cut-aways.

In another aspect, the shield electrodes may cover half or more of eachscan line.

In another aspect, the shield electrodes may be formed from the samematerial as the pixel electrodes.

In another aspect, the common electrodes may be formed with a comb-likeshape in the regions delimited by the scan lines and signal lines, andthe pixel electrodes, likewise of a comb-like shape, be formed so as toenclose the spaces around the peripheries of the comb-shaped commonelectrodes.

In another aspect, the common electrodes may be formed so as to coverthe regions delimited by the scan lines and signal lines, and the pixelelectrodes may be formed over the common electrodes, with an insulatorinterposed, and be provided with multiple slits that are parallel to oneanother.

In another aspect, the comb-shaped common electrodes and pixelelectrodes, or the multiple slits, may be provided so as to be inclinedrelative to the scan lines or signal lines.

In another aspect, the comb-shaped common electrodes and pixelelectrodes inside the regions delimited by the scan lines and signallines may be provided so as each to be inclined in a different extensiondirection, leftward or rightward, to the other.

In another aspect, the common wires may be provided between the multiplescan lines, and the multiple slits be provided so as to be inclined indifferent directions to each other on the two sides of the common wires.

In another aspect, the numbers of slits provided on each of the twosides of the common wires may be equal.

In another aspect, the end portions of those slits on the two sides ofeach common wire that are closest thereto may be joined above the commonwire.

In another aspect, the TFTs that serve as switching elements may beprovided over the scan lines, close to points where the signal linesintersect therewith, and the shield electrodes be provided so as tocover over the scan lines except for the surfaces of the TFTs.

In another aspect, the signal lines may be provided in a crank shape ina direction crossing over the scan lines, and the multiple commonelectrodes and pixel electrodes be arranged in a delta layout.

Thanks to having a structure such as described above, the inventionyields the excellent advantages that will now be described. According toa transverse field type liquid crystal display panel of some aspects ofthe invention, shield electrodes constituted of conductive material areformed on the surface of the insulator over the scan lines, so that thehigh voltage signals applied to the scan lines are blocked by the shieldelectrodes, which means that the DC component that is applied from thescan lines to the liquid crystals located above the shield electrodes isrendered small, thus drastically reducing the burn-in that can occur ina transverse field type liquid crystal display panel due to the highvoltage signals applied to the scan lines. The shield electrodes maycover the scan lines entirely, or may cover a part thereof. Further, theshield electrodes may be in a “floating” state whereby they are notconnected electrically to anything.

The potential of the shield electrodes in such floating state mightbecome unstable, but according to another aspect of the invention, theshield electrodes are electrically connected to the common electrodes,so that the potential of the shield electrodes is stabilized, with theresult that the burn-in that can occur in a transverse field type liquidcrystal display panel due to the high voltage signals applied to thescan lines is further drastically reduced.

According to another aspect of the invention, to electrically connectthe shield electrodes to the common electrodes, the shield electrodesare extended to above the insulator at the cut-aways provided in part ofthe pixel electrodes, and such connection is effected via contact holes.In this way, the shield electrodes and common electrodes areelectrically connected in a structurally simple manner. In addition,electric field are also generated in the gap portions between the pixelelectrodes and shield electrodes, and the alignment of the liquidcrystal molecules is thereby regulated; as this is essentiallyequivalent to an increase in the aperture ratio for a transverse fieldtype liquid crystal display panel, a liquid crystal display panel isobtained that gives bright displays.

According to another aspect of the invention, to electrically connectthe shield electrodes to the common electrodes, the shield electrodesare extended to above the insulator at the cut-aways provided in part ofthe pixel electrodes, and are electrically connected to the commonelectrodes located on the two sides of each scan line via contact holes.In this way, the shield electrodes and common electrodes areelectrically connected in a structurally simple manner, and furthermore,multiple common electrodes lying in the direction crossing the scanlines will be connected in series, which effectively means that thecommon wires' resistance will become low. Thereby, what is termed the“wiring delay” will become small, so that the common electrodes'potential will be stabilized and the display quality of each pixel willbe improved.

In addition, electric field are also generated in the gap portionsbetween the pixel electrodes and shield electrodes, and the alignment ofthe liquid crystal molecules is thereby regulated; as this isessentially equivalent to an increase in the aperture ratio for atransverse field type liquid crystal display panel, a liquid crystaldisplay panel is obtained that gives bright displays.

According to a transverse field type liquid crystal display panel ofother aspects of the invention, the shield electrodes cover half or moreof each scan line, with the result that the influence exerted on theliquid crystal molecules, and hence on the pixel electrodes, by theelectric field arising from the high voltage signals applied to the scanlines is kept small, and therefore, burn-in phenomenon of the transversefield type liquid crystal display panel will be unlikely to occur. Itwould be undesirable for the extent of each scan line covered by theshield electrodes to be less than half, since the smaller such extentbecomes, the more marked is the burn-in phenomenon. In other words, inproportion as the extent of each scan line covered by the shieldelectrodes is large, the phenomenon of transverse field type liquidcrystal display panel burn-in will be less likely to occur.Additionally, the broad width of the shield electrodes means that theirelectrical resistance is small, so that what is termed the “wiringdelay” will be short and the display quality of each pixel will beimproved.

According to another aspect, the shield electrodes are formed from thesame material as the pixel electrodes, which means that the shieldelectrodes can be formed simultaneously with formation of the pixelelectrodes and thus there is no need for an increase in time and processespecially in order to form the shield electrodes.

According to another aspect, the shield electrodes are electricallyconnected to the signal lines, with the result that the shieldelectrodes' potential varies depending on the signals applied to thesignal lines, but since the DC component of the signals applied to thesignal lines is small, and moreover the high voltage signals applied tothe scan lines are blocked out by the shield electrodes, the DC fieldapplied from the scan lines to the liquid crystals located above theshield electrodes is effectively eliminated, and thereby the burn-inphenomenon due to the high voltage signals applied to the scan lines ina transverse field type liquid crystal display panel is drasticallyreduced.

According to another aspect, to electrically connect the shieldelectrodes to the scan lines, the shield electrodes are extended to theintersections between the scan lines and signal lines, and suchconnection is effected via contact holes. In this way, the shieldelectrodes and scan lines are electrically connected in a structurallysimple manner.

According to another aspect, the advantages of the invention can beyielded satisfactorily even if the transverse field type liquid crystaldisplay panel is an IPS mode liquid crystal display panel with comb-likecommon and pixel electrodes that enclose the spaces around each other'speripheries.

According to another aspect, comb-like common electrodes and pixelelectrodes in an IPS mode liquid crystal display panel are provided soas to be inclined relative to the scan lines or signal lines, whichmeans that a minute-angle inclination can be formed between the pixelelectrodes and the rubbing direction of the alignment layer, so that anIPS mode liquid crystal display panel is obtained that has good contrastand other display characteristics while also yielding the advantages ofthe invention.

According to another aspect, comb-like common electrodes and pixelelectrodes in an IPS mode liquid crystal display panel are provided soas each to be inclined in a different direction, leftward or rightward,in the regions delimited by the scan lines and signal lines, thusproducing dual domains. Thereby, color variation depending on theviewing angle is eliminated, and hence an IPS mode liquid crystaldisplay panel is obtained that has good display characteristics whilealso yielding the advantages of the invention.

According to another aspect, the advantages of the invention can beyielded satisfactorily even if the transverse field type liquid crystaldisplay panel is an FFS mode liquid crystal display panel with commonelectrodes that are formed in the regions delimited by the scan linesand signal lines, and with pixel electrodes that have multiple slits andare formed over the common electrodes with an insulator interposed.

According to another aspect, the slits in an FFS mode liquid crystaldisplay panel are provided so as to be inclined relative to the scanlines or signal lines, which means that a minute-angle inclination canbe formed between the pixel electrodes and the rubbing direction of thealignment layer, so that an FFS mode liquid crystal display panel isobtained that has good contrast and other display characteristics whilealso yielding the advantages of the invention.

According to another aspect, the common wires are provided between themultiple scan lines, and furthermore the multiple slits in an FFS modeliquid crystal display panel are provided so as to be inclined indifferent directions to each other on the two sides of the common wires,thus producing dual domains. Thereby, color variation depending on theviewing angle is eliminated, and hence an FFS mode liquid crystaldisplay panel is obtained that has good display characteristics whilealso yielding the advantages of the invention.

Usually the common wires will be fabricated from the same conductivematerial as the scan lines and therefore be opaque, but according to afurther aspect of the invention, the end portions of those slits on thetwo sides of each common wire that are closest thereto are joined abovethe common wire, so that the common wire blocks light at thedisclination portions that occur at the positions where the slit setsinclined in different directions to each other are adjacent. As aresult, an FFS mode liquid crystal display panel is obtained that hasgood display characteristics while also yielding the advantages of theinvention.

According to a still further aspect, the TFTs that serve as switchingelements are provided over the scan lines, close to the points where thesignal lines intersect therewith, so that the pixel electrodes can berendered larger to the extent of the space thereby created. In addition,the shield electrodes are provided so as to cover over the scan linesexcept for the surfaces of the TFTs, so that the operation of the TFTswill not be affected by the shield electrodes' potential. Thus, atransverse field type liquid crystal display panel is obtained thatexhibits stable display characteristics while yielding the advantages ofthe invention.

According to a yet further aspect, the signal lines are provided in acrank-shape in the direction crossing over the scan lines, and themultiple common electrodes and pixel electrodes are arranged in a deltalayout (also termed a triad layout). As a result, the black matricesthat are provided in the portions opposed to the signal lines will notform straight lines and therefore will be inconspicuous, so that atransverse field type liquid crystal display panel is obtained that iswell suited for image displays while yielding the advantages of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described with reference to the accompanying drawings,wherein like numbers reference like elements.

FIG. 1 is a schematic plan view of two pixel portions of an FFS modeliquid crystal display panel of a first embodiment, seen through thecolor filter substrate.

FIG. 2 is a cross-sectional view along line II-II in FIG. 1.

FIG. 3 is a schematic plan view of two pixel portions of an FFS modeliquid crystal display panel of a second embodiment, seen through thecolor filter substrate.

FIG. 4 is a cross-sectional view along line IV-IV in FIG. 3.

FIG. 5 is a schematic plan view of two pixel portions of an FFS modeliquid crystal display panel of a third embodiment, seen through thecolor filter substrate.

FIG. 6 is a cross-sectional view along line VI-VI in FIG. 5.

FIG. 7 is a schematic plan view of four pixel portions of an FFS modeliquid crystal display panel of a fourth embodiment, seen through thecolor filter substrate.

FIG. 8 is a cross-sectional view along line VIII-VIII in FIG. 7.

FIG. 9 is a cross-sectional view along line IX-IX in FIG. 7.

FIG. 10 is a schematic plan view of a single pixel portion of an IPSmode liquid crystal display panel of the related art.

FIG. 11 is a cross-sectional view along line XI-XI in FIG. 10.

FIG. 12 is a cross-sectional view along line XII-XII in FIG. 10.

FIG. 13 is a schematic plan view of a single pixel portion of an FFSmode liquid crystal display panel of the related art.

FIG. 14 is a cross-sectional view along line XIV-XIV in FIG. 13.

FIG. 15 is a cross-sectional view along line XV-XV in FIG. 13.

FIG. 16 is a schematic plan view of another FFS mode liquid crystaldisplay panel of the related art.

FIG. 17 is a schematic plan view of a related art FFS mode liquidcrystal display panel with dual domains.

FIG. 18 is a schematic plan view of a related art FFS mode liquidcrystal display panel with delta layout.

FIG. 19 is a schematic plan view of an IPS mode liquid crystal displaypanel corresponding to the item in FIG. 16.

FIG. 20 is a schematic plan view of an IPS mode liquid crystal displaypanel corresponding to the item in FIG. 17.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the invention will now be described withreference to the accompanying drawings. It should be understood howeverthat the FFS mode liquid crystal display panels in the followingembodiments are described by way of examples of transverse field typeliquid crystal display panels embodying the technical thought of theinvention, and are not intended to limit the invention to theseparticular FFS mode liquid crystal display panels. The invention canequally well be adapted to yield other embodiments of FFS mode liquidcrystal display panels, etc., within the scope and spirit of the claims.

First Embodiment

An FFS mode liquid crystal display panel 10A of a first embodiment ofthe invention is described below by recounting the process of itsmanufacture, using FIGS. 1 and 2. FIG. 1 is a schematic plan view of twopixel portions of the FFS mode liquid crystal display panel of the firstembodiment, seen through the color filter substrate, and FIG. 2 is across-sectional view along line II-II in FIG. 1.

According to the first embodiment of the invention, an array substrateAR of the FFS mode liquid crystal display panel 10A includes atransparent substrate 11 constituted by a substrate of glass or thelike, over the entire surface of which a 2-layer film composed of alower layer of aluminum (Al) metal and a surface layer of molybdenum(Mo) metal is formed, from which film there are then formed, byphotolithographic and etching methods, multiple scan lines 12 and commonwires 13, lying parallel to each other and including Mo—Al 2-layerwiring lines. Aluminum has the merit that its resistance is low, but onthe other hand has the shortcomings of being prone to corrosion andhaving high contact resistance with ITO. Accordingly, a structurewhereby the aluminum is covered over with molybdenum is adopted so as toameliorate such shortcomings. The common wires 13 are provided alongsidescan lines in the example given here, but could alternatively beprovided between adjacent scan lines 12.

Next, the entire surface of the transparent substrate 11 with the scanlines 12 and common wires 13 formed thereon is covered with atransparent conductive layer constituted of, for instance, ITO, fromwhich common electrodes 14 are then formed, again usingphotolithographic and etching methods. The common electrodes 14 areelectrically connected to the common wires 13, but are not connected tothe scan lines 12 or gate electrodes G. The entire surface is furthercovered with a gate insulator 15 constituted of a silicon nitride orsilicon oxide layer, then the entire surface of the gate insulator 15 iscovered with a layer of, for instance, amorphous silicon (“a-Si” below)via the CVD method, after which a semiconductor layer 16 constituted ofan a-Si layer is formed in the TFT formation areas, once again usingphotolithographic and etching methods. The regions of the scan lines 12at the positions where the semiconductor layer 16 is formed form thegate electrodes G of the TFTs.

Next, the entire surface of the transparent substrate 11 with thesemiconductor layer 16 formed thereon is covered with an Mo—Al—Mo3-stratum conductive layer, from which signal lines 17 and drainelectrodes D are then formed, once again using photolithographic andetching methods. The source electrode S portions of the signal lines 17,and the drain electrode D portions, both overlap partially with thesurface of the semiconductor layer 16. Further, the entire surface ofthe substrate is then covered with an insulator constituted of a siliconnitride layer.

Next, contact holes 19 are formed in the positions in the insulator 18that correspond to the drain electrodes D, so as to partially expose thedrain electrodes D. Following that, the entire surface is covered with atransparent conductive layer constituted of, for instance, ITO, fromwhich, once again using photolithographic and etching methods, pixelelectrodes 21 having slits 20 are then formed over the regions of theinsulator 18 that are enclosed by the scan lines 12 and signal lines 17,in the pattern shown in FIG. 1, and moreover, shield electrodes 22 areformed to extend part-way over the surface of the insulator 18 lyingover the scan lines 12. The pixel electrodes 21 are electricallyconnected to the drain electrodes D via the contact holes 19, whereasthe shield electrodes 22 are not connected to anything, being in afloating state. So that they will not affect the operatingcharacteristics of the TFTs, the shield electrodes 22 will preferablynot cover the surface of the semiconductor layer 16. Also, the shieldelectrodes 22 may be formed from aluminum or a like conductive metalinstead of from ITO.

In addition, if necessary a passivation layer (not shown in thedrawings) constituted of, for instance, silicon nitride is provided overthe entire surface, and a predetermined alignment layer 24 is formedover the entire surface of the passivation layer. Thereupon, the arraysubstrate AR is complete. Subsequently, to obtain the FFS mode liquidcrystal display panel 10A of the embodiment, the array substrate ARfabricated in the foregoing manner is positioned facing a separatelyfabricated color filter substrate, the peripheries of the two substratesare sealed with sealing material, and liquid crystal is poured into thespace therebetween. As the configuration of the color filter substrateessentially does not differ from that in the related art describedearlier, detailed descriptions thereof are omitted.

In the FFS mode liquid crystal display panel 10A of the first embodimentobtained in the foregoing manner, at least a part of the surface of eachscan line 12 is covered by a conductive shield electrode 22. Thanks tothis, the liquid crystals will not be driven by the DC field generatedby the high voltage signals applied to the scan lines 12, andconsequently the FFS mode liquid crystal display panel burn-inphenomenon will be drastically reduced.

Second Embodiment

With the FFS mode liquid crystal display panel 10A of the firstembodiment, the shield electrodes 22 are in a floating state, whichmeans that the potential of the shield electrodes 22 could becomeunstable due to the influence of external fields, and fluctuatemarkedly. Accordingly, an FFS mode liquid crystal display panel 10B of asecond embodiment stabilizes the potential of the shield electrodes 22by electrically connecting the shield electrodes 22 to the commonelectrodes 14. Such FFS mode liquid crystal display panel 10B of thesecond embodiment will now be described using FIGS. 3 and 4. FIG. 3 is aschematic plan view of two pixel portions of the FFS mode liquid crystaldisplay panel of the second embodiment, seen through the color filtersubstrate, and FIG. 4 is a cross-sectional view along line IV-IV in FIG.3. Component elements in FIGS. 3 and 4 that have identical structure tothose in the FFS mode liquid crystal display panel 10A of the firstembodiment shown in FIGS. 1 and 2 are assigned the identical referencenumerals and detailed descriptions thereof are omitted.

The FFS mode liquid crystal display panel 10B of the second embodimentdiffers from the FFS mode liquid crystal display panel 10A of the firstembodiment in that a cut-away 25 is provided at a corner portion of eachpixel electrode 21 on an edge that is close to the shield electrode 22,part of the shield electrode 22 is extended to the cut-away 25, leavinga gap 26 with the pixel electrode 21, and the shield electrode 22 iselectrically connected to the common electrode 14 via a contact hole 27provided in the cut-away 25.

The fabrication process for the FFS mode liquid crystal display panel10B of the second embodiment is the same as that described above for theFFS mode liquid crystal display panel 10A of the first embodiment as faras the stage where, following formation of the signal lines 17 and drainelectrodes D, the entire surface of the substrate is covered with aninsulator 18 constituted of a silicon nitride layer. Next, contact holes19 and 27 are formed in the insulator 18 at the positions correspondingto the drain electrodes D and cut-aways 25, so as to expose a part ofeach drain electrode D and of each common electrode 14.

Further, the entire surface is covered with a transparent conductivelayer of, for instance, ITO, after which, using photolithographic andetching methods, pixel electrodes 21 having slits 20 and a cut-away 25are formed over the insulator 18 at the regions enclosed by the scanlines 12 and signal lines 17, in the patterns shown in FIG. 3, and inaddition, shield electrodes 22 are formed over the insulator 18 so as tostraddle the surface of the scan lines 12 and extend to the cut-aways25, but leaving gaps 26 with the pixel electrodes 21. Thereby, the pixelelectrodes 21 are electrically connected to the drain electrodes D viathe contact holes 19, and the shield electrodes 22 are electricallyconnected to the common electrodes 14 via the contact holes 27. Theremainder of the fabrication process is the same as that for the FFSmode liquid crystal display panel 10A of the first embodiment.

According to this FFS mode liquid crystal display panel 10B of thesecond embodiment, the shield electrodes 22 are electrically connectedto the common electrodes 14 via the contact holes 27, thanks to which,the shield electrodes 22 have stable potential and hence are unlikely tobe affected by electric field from the exterior, and furthermore, theliquid crystals will not be driven by the DC field generated by the highvoltage signals applied to the scan lines 12. Consequently, the burn-inphenomenon will be drastically reduced in the FFS mode liquid crystaldisplay panel 10B. In addition, according to the FFS mode liquid crystaldisplay panel 10B of the second embodiment, although one slit 20 ₁ isrendered shorter by the provision of a cut-aways 25 in each pixelelectrode 21, the fact that electric fields are generated not onlybetween the pixel electrode 21 and the common electrode 14 but alsobetween the pixel electrode 21 and shield electrode 22 means that thegaps 26 between the pixel electrodes 21 and the shield electrodes 22 atthe cut-aways 25 exert effects essentially equivalent with those of theslits 20 provided in the pixel electrodes 21. Thus, the gap 26 portionstoo serve as effective display areas, and consequently the apertureratio is improved.

Third Embodiment

Whereas in the FFS mode liquid crystal display panel 10B of the secondembodiment the potential of the shield electrodes 22 is stabilized byelectrically connecting the shield electrodes 22 to the commonelectrodes 14 so as not to be affected by fields from the exterior, inan FFS mode liquid crystal display panel 10C of a third embodiment thepotential of the shield electrodes 22 is stabilized by electricallyconnecting the shield electrodes 22 to the signal lines 17. This FFSmode liquid crystal display panel 10C of the third embodiment will nowbe described using FIGS. 5 and 6. FIG. 5 is a schematic plan view of twopixel portions of the FFS mode liquid crystal display panel of the thirdembodiment, seen through the color filter substrate, and FIG. 6 is across-sectional view along line VI-VI in FIG. 5. Component elements inFIGS. 5 and 6 that have identical structure to those in the FFS modeliquid crystal display panel 10A of the first embodiment shown in FIGS.1 and 2 are assigned the identical reference numerals and detaileddescriptions thereof are omitted.

The FFS mode liquid crystal display panel 10C of the third embodimentdiffers from the FFS mode liquid crystal display panel 10A of the firstembodiment in that the shield electrodes 22 are extended to positionsover the insulator 18 lying over the scan lines 12 that correspond tothe intersections of the adjacent signal lines 17 therewith, and theshield electrodes 22 are electrically connected to the signal lines 17via contact holes 28 provided in the insulator 18 at the positionscorresponding to such intersections.

The fabrication process for the FFS mode liquid crystal display panel10C of the third embodiment is the same as that described above for theFFS mode liquid crystal display panel 10A of the first embodiment as faras the stage where, following formation of the signal lines 17 and drainelectrodes D, the entire surface of the substrate is covered with aninsulator 18 constituted of a silicon nitride layer. Next, contact holes19 and 28 are formed in the insulator 18 at the positions correspondingto the drain electrodes D and the intersections between the scan lines12 and the signal lines 17, so as to expose a part of each drainelectrode D and of each signal line 17.

Further, the entire surface is covered with a transparent conductivelayer of, for instance, ITO, after which, using photolithographic andetching methods, pixel electrodes 21 having slits 20 are formed over theinsulator 18 at the regions enclosed by the scan lines 12 and signallines 17, in the patterns shown in FIG. 5, and in addition, shieldelectrodes 22 are formed on those parts of the insulator 18 that arelocated over the surfaces of the scan lines 12. Thereby, the pixelelectrodes 21 are electrically connected to the drain electrodes D viathe contact holes 19, and the shield electrodes 22 are electricallyconnected to the signal lines 17 via the contact holes 28. The remainderof the fabrication process is the same as that for the FFS mode liquidcrystal display panel 10A of the first embodiment.

According to this FFS mode liquid crystal display panel 10C of the thirdembodiment, the shield electrodes 22 are electrically connected to thesignal lines 17 via the contact holes 28, thanks to which, even if thepotential of the shield electrodes 22 varies due to the signals appliedto the signal lines 17, the DC component thereof will be small.Consequently, the liquid crystals will be affected only to a smallextent by signal line 17 signals applied to the shield electrodes 22,besides being unlikely to be affected by electric field from theexterior, and in addition, the liquid crystals will not be driven by theelectric field that is generated by the high voltage signals applied tothe scan lines 12. As a result, the FFS mode liquid crystal displaypanel burn-in phenomenon will be drastically reduced.

Fourth Embodiment

An FFS mode liquid crystal display panel 10D of a fourth embodiment ofthe invention is described below by recounting the process of themanufacture thereof, using FIGS. 7 to 9. FIG. 7 is a schematic plan viewof four pixel portions of the FFS mode liquid crystal display panel ofthe fourth embodiment, seen through the color filter substrate, FIG. 8is a cross-sectional view along line VIII-VIII in FIG. 7, and FIG. 9 isa cross-sectional view along line IX-IX in FIG. 7. Component elements inFIGS. 7 to 9 that have identical structure to those in the FFS modeliquid crystal display panel 10A of the first embodiment shown in FIGS.1 and 2 are assigned the identical reference numerals and detaileddescriptions thereof are omitted.

According to the fourth embodiment of the invention, an array substrateAR of the FFS mode liquid crystal display panel 10D has a transparentsubstrate 11 constituted by a substrate of glass or the like, over theentire surface of which 2-layer composed of a lower layer of Al metaland a surface layer of Mo metal is formed, from which layer there arethen formed, by photolithographic and etching methods, multiple scanlines 12 and multiple common wires (omitted from the drawings), lyingparallel to each other and including Mo—Al 2-layer wiring lines. Thecommon wires are provided alongside the scan lines 12 in the examplegiven here, but could alternatively be provided between adjacent scanlines 12.

Next, the entire surface of the transparent substrate 11 with the scanlines 12 and common wires formed thereon is covered with a transparentconductive layer constituted of, for instance, ITO, from which commonelectrodes 14 are then formed, again using photolithographic and etchingmethods. The common electrodes 14 are electrically connected to thecommon wires, but are not connected to the scan lines 12 or gateelectrodes G. The entire surface is further covered with a gateinsulator 15 constituted of a silicon nitride or silicon oxide layer,then the entire surface of the gate insulator is covered with a layerof, for instance, amorphous silicon (“a-Si” below) via the CVD method,after which a semiconductor layer 16 constituted of an a-Si layer isformed in the TFT formation areas, once again using photolithographicand etching methods. The regions of the scan lines 12 at the positionswhere the semiconductor layer 16 is formed form the gate electrodes G.

Next, the entire surface of the transparent substrate 11 with thesemiconductor layer 16 formed thereon is covered with an Mo—Al—Mo3-stratum conductive layer, from which signal lines 17 with a sourceelectrode S portion, and drain electrodes D, are then formed, once againusing photolithographic and etching methods. The source electrode Sportions of the signal lines 17 and the drain electrode D portions bothoverlap partially with the surface of the semiconductor layer 16.Further, the entire surface of the substrate is then covered with aninsulator 18 constituted of a silicon nitride layer.

Next, contact holes 19, 27 ₁ and 27 ₂ are formed in the positions in theinsulator 18 that correspond to the cut-aways 25 ₁ and 25 ₂ describedhereafter, so as to expose a part of each drain electrode D and a partof each common electrode 14. Following that, the entire surface iscovered with a transparent conductive layer constituted of, forinstance, ITO, from which, once again using photolithographic andetching methods, pixel electrodes 21 having slits 20, as well ascut-aways 25 ₁ and 25 ₂ each located in a corner portion of one of theedges adjacent to the scan lines 12, are then formed over the regions ofthe insulator 18 that are enclosed by the scan lines 12 and signal lines17, in the pattern shown in FIG. 7. Shield electrodes 22 also are formedon the insulator 18, across the surface of the scan lines 12 so as tostraddle the cut-aways 25 ₁ and 25 ₂ on the two sides thereof, andleaving respective gaps 26 ₁ and 26 ₂ with the pixel electrode.

Thus, the pixel electrodes 21 are electrically connected to the drainelectrodes D via the contact holes 19, and the shield electrodes 22 areelectrically connected to the common electrodes 14 on the two sides ofthe scan lines 12 via the contact holes 27 ₁ and 27 ₂. Hence, the commonelectrodes 14 on the two sides of each scan line 12 are electricallyconnected to each other across the scan line 12 by the shield electrode22.

As a further step, a predetermined alignment layer 24 is formed over theentire surface, whereupon the array substrate AR is complete.Subsequently, to obtain the FFS mode liquid crystal display panel 10D ofthe fourth embodiment, the array substrate AR fabricated in theforegoing manner is positioned facing a separately fabricated colorfilter substrate, the peripheries of the two substrates are sealed withsealing material, and liquid crystal is poured into the spacetherebetween. As the configuration of the color filter substrateessentially does not differ from that in the related art describedearlier, detailed descriptions thereof are omitted.

In the FFS mode liquid crystal display panel 10D of the fourthembodiment obtained in the foregoing manner, at least a part of thesurface of each scan line 12 is covered by the conductive shieldelectrodes 22. Thanks to this, the liquid crystals will not be driven bythe DC field generated by the high voltage signals applied to the scanlines 12, and consequently the FFS mode liquid crystal display panelburn-in phenomenon will be drastically reduced. Also, the shieldelectrodes 22 are electrically connected to the common electrodes 14located on the two sides of the scan lines 12 via the contact holes 27 ₁and 27 ₂; consequently, the shield electrodes 22 have stable potentialand therefore are unlikely to be affected by fields from the exterior,and moreover, the liquid crystals will not be driven by the DC fieldthat is generated by the high voltage signals applied to the scan lines12. Hence, the burn-in phenomenon will be drastically reduced in the FFSmode liquid crystal display panel 10D.

Further, according to this FFS mode liquid crystal display panel 10D,although some of the slits, i.e., slits 20 ₁, are rendered shorter bythe provision of the cut-aways 25 ₁ and 25 ₂ in the pixel electrodes 21,the fact that electric fields are generated not only between the pixelelectrodes 21 and the common electrodes 14 but also between the pixelelectrodes 21 and shield electrodes 22 means that the gaps 26 ₁ and 26 ₂between the pixel electrodes 21 and the shield electrodes 22 at thecut-aways 25 ₁ and 25 ₂ exert effects that are essentially equivalentwith those of the slits 20 provided in the pixel electrode 21. Thus, thegap 26 _(i) and 26 ₂ portions too serve as effective display areas, andconsequently the aperture ratio is improved.

In addition, according to this FFS mode liquid crystal display panel10D, the common electrodes 14 on the two sides of the scan lines 12 areelectrically connected across the scan lines 12 by the shield electrodes22, which means that all the common electrodes 14 aligned in a directioncrossing over the scan lines 12 are connected in series via the shieldelectrodes 22. As a result, the common wires' resistance effectivelybecomes low, so that what is termed the “wiring delay” becomes small.Thereby, the common electrodes' potential is stabilized and an FFS modeliquid crystal display panel is obtained in which each pixel has gooddisplay quality.

The first to fourth embodiments represent examples where the scan lines12 and signal lines 17 are provided so as to cross over one another instraight lines. But alternatively, the signal lines 17 may be providedin a crank-shape in a direction orthogonal to the scan lines 12, and themultiple common electrodes 14 and pixel electrodes 21 may be arranged ina delta layout, so that the black matrices provided on the color filtersubstrate in the portions opposed to the signal lines 17 will not formstraight lines, and the device will be capable of image displays inwhich the black matrices are inconspicuous, as in the related art FFSmode liquid crystal display panel 70D shown in FIG. 18. As anotheralternative, the stripe-like slits provided in the pixel electrodes maybe arranged in two mutually inclined sets, one above the other, thusproducing dual domains, as in the related art FFS mode liquid crystaldisplay panel 70C shown in FIG. 17. If the slits are arranged in thisway to produce dual domains, it will be preferable to make the numbersof slits inclined in each direction equal, since this will prevent colorvariation depending on the viewing angle. It will also be preferable tojoin together the ends of those slits on the two sides of the commonwire that are closest thereto, or in other words, the ends of the pairof slits—one in each of the mutually inclined sets—that are positionedclosest to each other, since this will block light at the disclinationportions that occur at such portions.

Although the first to fourth embodiments represent examples where theslits provided in the pixel electrodes 21 are inclined in a singledirection, it will alternatively be possible, as in the related art FFSmode liquid crystal display panel 70C shown in FIG. 17, to arrange thestripe-like slits 77C provided in the pixel electrodes 78C in twomutually inclined sets, one above the other, thereby producing dualdomains. In such a case, in order to reduce the viewing angle anisotropyto a low level, the numbers of slits 77C provided on each of the twosides of the common wire 73 will preferably be equal, and the ends ofthose slits on the two sides of each common wire 73 that are closestthereto will preferably be joined together over the common wire 73. Afurther alternative would be, as in the related art FFS mode liquidcrystal display panel 70D shown in FIG. 18, to provide the signal lines74 in a crank-shape in a direction orthogonal to the scan lines 72, andto arrange the multiple common electrodes and pixel electrodes 78D in adelta layout, so that the black matrices provided on the color filtersubstrate in the portions opposed to the signal lines 17 will not formstraight lines, and the device will be capable of image displays inwhich the black matrices are inconspicuous.

In addition, the configuration of the FFS mode liquid crystal displaypanels 10A to 10D described in the first to fourth embodiments above—andin particular the configuration relating to the shield electrodes 22—canreadily be adapted into an IPS mode liquid crystal display panel such asshown in FIGS. 10 to 12. To avoid duplication of description however,descriptions of the configurations of the present invention when adaptedto an IPS mode liquid crystal display panel are omitted herein.Furthermore, it is plainly evident that when the present invention isadapted to IPS mode liquid crystal display panels, it will be possible,as in the related art IPS mode liquid crystal display panels 50B and 50Cshown in FIGS. 19 and 20, to provide the pixel electrodes and commonelectrodes inclined at a slight angle to the alignment layer's rubbingdirection, to arrange the pixel electrodes and common electrodes each tobe inclined in a different extension direction, leftward or rightward,to the other, thereby producing dual domains, and to arrange the pixelelectrodes and common electrodes in a delta layout.

1. A transverse field type liquid crystal display panel comprising:multiple scan lines and common wires provided in parallel; multiplesignal lines provided in a direction crossing the scan lines; and commonelectrodes and pixel electrodes formed in regions delimited by the scanlines and signal lines, shield electrodes constituted of a conductivematerial being formed on a surface of an insulator lying over the scanlines.
 2. The transverse field type liquid crystal display panelaccording to claim 1, wherein the shield electrodes are electricallyconnected to the common electrodes.
 3. The transverse field type liquidcrystal display panel according to claim 2, wherein the pixel electrodespartially have cut-aways provided close to the shield electrodes, andthe shield electrodes are extended to above the insulator at thecut-aways and electrically connected to the common electrodes viacontact holes provided in the cut-aways.
 4. The transverse field typeliquid crystal display panel according to claim 1, wherein the shieldelectrodes are electrically connected to the signal lines.
 5. Thetransverse field type liquid crystal display panel according to claim 4,wherein the shield electrodes are extended over the surface of theinsulator over the scan lines as far as the intersections of the scanlines and signal lines, and are electrically connected to the signallines via contact holes provided at the intersections.
 6. The transversefield type liquid crystal display panel according to claim 1, whereinthe pixel electrodes partially have cut-aways provided adjacent to thetwo sides of the scan lines, and the shield electrodes are extended toabove the surface of the insulator over the cut-aways and areelectrically connected to each of the common electrodes located on thetwo sides of the scan lines.
 7. The transverse field type liquid crystaldisplay panel according to claim 6, wherein the shield electrodes coverhalf or more of each scan line.
 8. The transverse field type liquidcrystal display panel according to claim 1, wherein the shieldelectrodes are formed from the same material as the pixel electrodes. 9.The transverse field type liquid crystal display panel according toclaim 1, wherein the common electrodes are formed with a comb-like shapein the regions delimited by the scan lines and signal lines, and thepixel electrodes, likewise of a comb-like shape, are formed so as toenclose the spaces around the peripheries of the comb-shaped commonelectrodes.
 10. The transverse field type liquid crystal display panelaccording to claim 9, wherein the comb-shaped common electrodes andpixel electrodes are provided so as to be inclined relative to the scanlines or signal lines.
 11. The transverse field type liquid crystaldisplay panel according to claim 10, wherein the comb-shaped commonelectrodes and pixel electrodes inside the regions delimited by the scanlines and signal lines are provided so as each to be inclined in adifferent extension direction, leftward or rightward, to the other. 12.The transverse field type liquid crystal display panel according toclaim 1, wherein the common electrodes are formed so as to cover theregions delimited by the scan lines and signal lines, and the pixelelectrodes are formed over the common electrodes, with an insulatorinterposed, and provided with multiple slits that are parallel to oneanother.
 13. The transverse field type liquid crystal display panelaccording to claim 12, wherein the multiple slits are provided so as tobe inclined relative to the scan lines or the signal lines.
 14. Thetransverse field type liquid crystal display panel according to claim13, wherein the common wires are provided between the multiple scanlines, and the multiple slits are provided so as to be inclined indifferent directions to each other on the two sides of the common wires.15. The transverse field type liquid crystal display panel according toclaim 14, wherein the numbers of slits provided on each of the two sidesof the common wires are equal.
 16. The transverse field type liquidcrystal display panel according to claim 14, wherein the end portions ofthose slits on the two sides of each common wire that are closestthereto are joined above the common wire.
 17. The transverse field typeliquid crystal display panel according to claim 1, wherein TFTs (thinfilm transistors) that serve as switching elements are provided over thescan lines, close to points where the signal lines intersect therewith,and the shield electrodes are provided so as to cover over the scanlines except for the surfaces of the TFTs.
 18. The transverse field typeliquid crystal display panel according to claim 1, wherein the signallines are provided in a crank shape in a direction orthogonal to thescan lines, and the multiple common electrodes and pixel electrodes arearranged in a delta layout.